1. Field of the Invention
This invention relates to a method for manufacturing a high-efficiency thermal conductive base board, more particularly to a method for manufacturing a high-efficiency thermal conductive base board having a metal substrate formed with a metal oxide layer through micro-arc oxidation.
2. Description of the Related Art
In the past, both heat dissipation and electrical insulation requirements for electronic and photoelectric components can be satisfied by using a plastic substrate since the heat resulting from operation of these components is not too high. Since information and communication products are in wide use nowadays, the need for electronic devices, such as dynamic random access memories (DRAM), in the market has increased, and manufacturing processes of the semiconductor and photoelectric components have progressed toward very large scale integration (VLSI). The heat dissipating problem for devices with multilevel interconnects is serious and cannot be disregarded.
As shown in FIG. 1, a conventional base board 1 used in electronic devices includes an aluminum substrate 11, an epoxy resin layer 12 formed on the aluminum substrate 11, and copper contacts 13 that are electrochemically plated on the epoxy resin layer 12.
It is noted that since the difference in surface properties between the epoxy resin layer 12 and the copper contacts 13 is relatively large, the copper contacts 13 can hardly bond to the epoxy resin layer 12. Hence, prior to electrochemical plating of the copper contacts 13 on the epoxy resin layer 12, a series of pre-treatments, such as roughening the surface of the epoxy resin layer 12, and sensitizing and activating the surface of the epoxy resin layer 12 via oxidation-reduction reaction, have to be conducted so as to improve adhesion of the copper contacts 13 to the epoxy resin layer 12.
The conventional base board 1 has the following drawbacks:
(1) The epoxy resin layer 12 has a thermal conductivity as low as 0.2 W/m/K that cannot meet current heat-dissipating requirements of the integrated circuit industry and that can result in a reduction in the service lives of components bonded to the substrate 11 due to such low thermal conductivity.
(2) Prior to electrochemical plating of the copper contacts 13, the surface of the epoxy resin layer 12 is required to be pre-treated, and such pre-treatment is complicated and costly.
(3) Since the surface of the epoxy resin layer 12 is required to be pre-treated by roughening, narrow line width of the integrated circuit cannot be achieved.
(4) Formation of the copper contacts 13 through electrochemical plating is a source of water pollution.